锆系Ziegler—Natta体系催化1—丁烯二聚中配体的影响

采用ＺｒＣｌ４／ＡｌＥｔ２Ｃｌ催化体系研究了不同配体如酚钠、三苯基膦等对１－丁烯二聚的影响，结果表明，给电子配体的加入能降低催化剂的活性，并显著地提高二体的选择性，但在强吸电子配体的存在下，（如三氟乙酸基），具有还原性的三苯基膦配体能将中心金属了子从４价还原３价，，从而使１－丁烯齐中二聚体的的选择性下降；另外，碱性配体能有效地防止１－丁烯异构成２－丁烯。基于用ＡｌＥｔ２Ｃｌ作助催化剂时产物中存在Ｃ

EFFECTS OF LIGANDS ON THE DIMERIZATION OF 1 BUTENE BASED ON THE ZIRCONIUM ZIEGLER NATTA CATALYTIC SYSTEM

C 8 olefins dimerized from 1 butene are used widely in the industry,e.g.manufacture of linear low density polyethylene (LLDPE) comonomers,special detergents,synthetic lubricating oils,etc.So dimerization of 1 butene is of considerable industrial interest as well as its academic value.In general,zirconium Ziegler Natta catalyst is used in polymerization of olefins.Few articles concerning the dimerization of 1 butene via modified zirconium Ziegler Natta catalyst were reported.The effects of different ligands such as PhONa,Ph 3P,etc.on the dimerization of 1 butene via ZrCl 4/AlEt 2Cl catalytic system have been studied in this paper.Results show that electrondonor ligands can decrease the catalyst activity and increase the selectivity of C 8 = dimers obviously.But when electrondonor ligands are in existence (e.g.trifluoroacetyl),the reductive Zr 4 ligand of Ph 3P will be reduced to Zr 3 ,will lead to the decrease of dimers.In addition,alkaline ligands can prevent isomerization of 1 butene to 2 butene effectively.Based on the facts that exist C 6 olefins in the products by using AlEt 2Cl as the promoter,while there are no C 6 olefins observed in the products by using n Bu 2Mg as the promoter,a metal hydride mechanism for the dimerization of 1 butene over zirconium Ziegler Natta catalyst is suggested.